Apparatus for the extraction of metals from their ores.



W. E. GREENAWALT. APPARATUS FOR THE EXTRACTION 0T METALS FROM THEIR 0333. I

APPLIGATION FILED FEB. 1 1904. RENEWED MAR. 30, 1908. I 901 ,61 1 Eatented Oct. 20, 1908.

WTNEssE. imvEQ-r on MAM QM of Colorado, have invented certain new 1 useful Improvements in Apparatus for the UNITED PATE OFFICE? WILLIAM E. GBEENAWALTpOF DENVER, coLon Do.

ArP'ARAcr-Us non THE EXTRACTION or METALS neon THEIR onus.

Application filed February 1, 1904, Serial No. 191,600.

To all whom it may concern:

Be it known that L'WILLIAM E. GREENA- WALT, a citizen of the United States, residing Specification of Letters Patent.

Patented Oct. 20, lacs.

Renewed March 30, 1908. Serial No. 424,117.

compared with making and applying liquid chlorin which requires low temperatures and high pressure to hquely 1t. Besides my at Denver, in the county of Denver and State method of applying the chlorin has marked Extraction of Metals from Their Ores, of which the following is a specification.

My invention relates to improvements in a paratus for the extraction of metals from t eir ores by the use of chlorin.

It is intended more particularly as an apparatus well designed to carry out my processes as described in my applications for recess patents, SerialNumber 47,975, filed ebruary 19, 1901; Serial Number 127,290, filed October14, 1902; and Serial Number 144,363, filed February 2-1, 1903; although I do not wish to limit its use to these processes alone.

The process, briefly described, consists in absorbing chlorin in aqueous solution under varying degrees of pressure whereby, according to Henrys law, a solution of chlorin obtained corresponding to the chlorin pressure used.

Henrys law states that the volume of the gas absorbed by tional to the pressure of the gas. If the pressure be doribledthe same volume of liqquid will dissolve twice the volume of the gas. Thus, if 100 volumes of Water at 10 centigrade dissolve two volumes of chlorin under the standard atmospheric pressure, under twice the pressure (two atmos heres) the same volume of Water will absorii twice the volume of chlorin, or four volumes. The solubility of chlorin in water under ordinary conditions is small. At or about 10 water will absorb about 25- times its volume of tlw gas. In ractice it Will usually be less. VV'ater, to t 1e extent of half the weight of the ore is ordinarily put/into a chlorina- Y tion barrel with the ore to make an easy flowing pulp. This amount of water, per ton of ore, can, under ordinary conditions, dissolve about 40 ounces bf chlorin. Usuall Y from 50 to 80 ounces are required. It will be seen from Henrys law just stated, that by doubling the pressure of the gas to about two atmos )heres or about 15 pounds per square inch, t at the fifty to eighty ounces required can readily be brought into solution. A pressure of 5 to, 25 pounds per square inch ought to treat the most refractory ore. It

and ,1 1m rovements over a liquid is directly proper-1 electrolytic ee methods of applying ch orin or chlorin generating compounds directly to the ore in the barrel as will appear later on in the s ecification.

The primary 0 ject of this probess and apparatus is to apply chlorin, as generated by electrolysis, to the reduction of gold ores without resorting to high pressures or low temperatures or without first combining the chlorin with an accessory compound, such as calcium hydrate to form bleaching pow- An essential feature of both my recess and apparatus consists in first absorbing the chlorin in the amount of Water required to make an easy flowing pulp with the ore, out side of the chlorinating vessel, and then introducing the solution and the ore into the vessel to be treated. With the small pressures used, there Will be no mechanical difiiculties in the manipulation.

The accom anying drawing illustrates my apparatus in detail fpr carrying out the process.

1 is an electrolytic cell for generating chlorin from sodium chlorid.

2 is a compressor which exhausts the chlorin from the ositive compartment of the lland forces it under suitable pressure into the closed absorption chamber 4. -When no pressure is necessary, by the proper adjustment of the valves, the chlorin is passed by the compressor directly into the absorption chamber. When only a small pressure is needed it can be best obtained by i Working the positive compartn'ient of the cell under pressure. This can do no harm. Indeed, it may be decidedly beneficial, in that it increases the pressure from the positive to the ne ative compartments and thus prevents the Tormation of hypochlorites by the mingling of the chlorin and caustic soda. throu h the diapl'iragm. In some cells this difiicu lty is minimized by keeping the caustic soda in the ne ative compartment at a lower i level than the brine in the positive compartment in others, Where the cathode is in intimate contact with the diaphragm, the nega-. tive compartment is vacant. The object in either case is the same, namely, to prevent the caustic soda from working back into the chlorin compartment by causing a flow in the lea Q comm opposite direction, due to unequal pressures in the compartments. The same results can be attained by working the positive compartment under pressure of the liberated chlorin gas, even if the liquid in' the negative compartment is at the same or higher level than the brine in the positive compartment.

In order to properly absorb the chlorin in water the chamber 4 is made with shelves which roject alternately from top to bot tom. hese shelves canbe made of various materials, such as lead or cement but they are best made of large sheets of plate glass. The idea of these shelves is to subdivide the water and increase'its surface by s reading it out in thin sheets and letting it ow from one shelf to the other whereby most favorable conditions are attained for quickly and thoroughly dissolving the chlorin.

In order to spread the water satisfactorily at its introduction into the chamber, nozzles 6 are so arranged as to introduce it into the upper compartment of the chamber in a fine spray. The spray also cfiers the greatest possible surfaoe to the chlorin. The water after it passes from one shelf to the other in an atmos here of chlorin issues from the chamber t rough the pipe 7 into the closed storage tank 8, where it is at all times ready for use.

10 is a chlorinatiug barrel into which the ore is placed for treatment with the chlorin solution.

It is evident that when a super saturated solution of chlorin is introduced into the.

barrel, unless the necessary precautions are taken, the pressure will'be momentarily released and much of the chlorin will no longer be held in solution but will difl'usc in the barrel as free gas. It would not be loin however before the gas in the barrel would acquire the same tension as the gas in the solution. There is no particular harm in this, for as the ehlorin in solution in the barrels is consumed more would be taken into solution.

If it should be desirable to introduce the supersaturated solution without the diffusion of free gas in the barrel, it can readily be done by first connecting the gas Suppl of the absorption chamber with the barrefby means of a pipe or conduit (5. Chlorin will then flow into the barrel until equilibrium is established in the gas pressure. The solution can then he introduced into the barrel through the pipe or conduit 9 under the same pressure as it is inv the absorption chamber. then all the chlorin which is in solution will remahl in solution while it is being introduced into the barrel and while the ore is being treated. A simple modification of this method of procedure would be to first absorb the chlorin under ordinary atmospheric conditions,in the amount of water required to make an easy flowing pulp and introduce the solution and the ore into the barrel. Gas eous chlorin under any desired pressure could then be forced in to furnish an excess which would be absorbed by the water as rapidly as the ehlorin in solution is consumed by'the ore. By this method it would not be necessaryin many instances to absorb the chlorin in the absorption chamber under pressure. An ordinaly solution might frequently suffice.

12 1s a tank in which the desired metals are precipitated out of the solution after treatment in the barrel. I

13 is a filter ress where the precipitated metals are cauglit and 14. a pump for returning the solution for resaturation and regeneraac tion and re-use. This is desirable only when there is silver or copper in the ore worth re covering, or when some other chemicals re in the solution which it is not desirable to." lose. 8-5

To operate the process and apparatus, a saturated solution of salt is allowed to flow into the .ositive compartment of the ele( lytic eel ,1. An electric current is passed from the anode to the cathode u 'hich. decomposes the salt. Chlorin is liberated in the positive compartment while caustic soda and hydrogen appear in the negative coin: pertinent. If the ore requires simply an or dinary solution of chlorin, it is pa octly 91'; from the cell to the absorption. 11 if only a small pressure is need will frequently suffice, the o partment of the cell is preferab trot der the pressure required. Shouldt uire a strong solution, it is preferably through the compressor 2 and force the absorption chamber under any desired. In this way the pressure c varied from zero upward, and the so. can be varied from the ordinary soiution, to one containing one or two per cent. and more of chlorin, and can be made to suit fthe varying ores. The water is introduced into... the absor tion chamber through the inlet 11o pipe 5 un er pressure at least slightly in excess of the highest ehlorin ressure likely to be used. As it flows over t ie shelves in thin sheets in an atmosphere of chlorin a soiution of chlorin is obtained corresponding to t so used. Fro; ,hrough pipe 7 1 hence it is drawn d."

In cha gin r the barrel, the amount of ore 13 first plalccd therei 12, or 1.1 are then opened to permit the es cape ofair' as the solution ecs its way down through the ore. This percolation may be facilitated by connecting the barrel toan exhaust pump, but this will not ordinarily be necessary. Valve 3 is then opened and chlorin allowed'to flow into the bars until e uilibrium in the ehlorin pressure chlerin pr solution 1 ex establis ed between the barrel and t,. ah

in en apjiaratus for thehydrometallurgica'l extraction of metals from their ores the combination of an electrolytic cell for'gene'r- I gas; means of forcing chlorin gas into said chamber under pressure greater thehatmospheric pressure; a chlorinating vessel in which the ore is treated with the solution so formed; means of introducing the solution into the chlorinating vessel, and means of filterinig the solution from the treated ore. 10. 1

1 an apparatus'for the hydrometallurgical extraction of metals from. their ores amen the combination of an electrolytic cell for generating chlor1n;a chamber, se erate and distinct from the electrolytic cei but com municating with the positive compartment thereof, in which the chlorin so generated is:- absorbed in a ueous solution; meansm said chamber of en dividing the solutionwhereby a larger surface is exposed to'the chlorin gas; means of forcing chlorin gas into said chamber under pressure greater than atmospheric pressure; a chlorinating vessel in which the ore is treated with the solution so formed; means of filtering the solution from the treated ore and means of returning the solution for regeneration and re-use.

winL Alyt QQREENAQWALT.

Witnesses: a I:

I RALPH 'L. PAenocK;-'

(FRANK RJFIELD. 

